Mill pulverizer



J. P. POLSTER MILL PULVERIZER April 8, 1930.

Filed May 2, 1929 I INVEN'TOR Patented Apr. 8, 1930 UNITED STATES PATENT OFFICE I JOHN IE. POLSTEIR, OF ALTON, ILLINOIS, ASSIGNOR TO ILLINOIS STOKER COMPANY, OF

ALTON, ILLINOIS,A CORPORATION OF ILLINOIS MILL PULVERIZER Application filed May 2, 1929. Serial No. 359,874.

This invention relates to certain new and useful improvements in mill pulverizers for coal, petroleum coke and other suitable material, the peculiarities of which will be hereinafter fully described and claimed.

The main objects of my invention are to provide for feeding the material around the whole periphery of the pulverizing rotor in the mill; secondly,.around such periphery at each end of said rotor and then laterally into both ends of a central pulverizing chamber;

thirdly, to effect such lateral feeding into the spaces between the pulverizing hammers; fourthly, to feed and discharge through the same opening; and fifthly, to eflect other improvements hereinafter described and claimed.

In the accompanying drawing in which like reference numerals indicate corresplonding parts,

Fig. 1 represents a vertical longitudinal section near the center of a mill pulverizer em: bodying my improvements;

ig. 2, a cross section on the line 22 of Fig. 1; and

Fig. 3, an end elevation of the same on a reduced scale with a separator mounted there- Referring to the drawing, the numeral 1 designates a shaft centrally mounted in a horizontal cylindrical casing 2 having bearings 3 at the ends thereof, and adapted to be rotated by direct-connected motor or pulley drive (not shown).

The casing isv preferably in three flanged sections and ends, provided with holes for through rods or other fastening means.

Midway in said casing is mounted on said shaft two pairs (or more) of discs 4 having holes circumferentially arranged for pivot pins 5, on which are pivotally mounted a set of stirrup hammers (four being shown),

preferably of the form illustrated and described in my pending application Serial No. 261,471,-but they may be of other suitable form. The heads of these pulverizing hammers consist of parallel spaced bars (Fig. 2) radially disposed, and forming openings for the passage of material being reduced, as fully described in said prior application.

tion.

hammers, and also preferably hold said pivotpins from end play in the disc holes, as shown in Fig. 1. v

The central part of the. casing cooperating with these hammers in the pulverizing operation is a complete circle constituting a bull ring cage 8, of smooth or otherwise inner surface adjacent to the heads of said hammers, and preferably made in a detachable section from the outer sections that have openings'9 at the'top (or elsewhere). The casing is thus cylindrical or substantially barrel-shaped wlth openings near orat the ends on top (preferred) for the entrance of feed material and the dischargeof finished product, as will be described later.

On said central shaft in the outer sections are mounted other discs 10 in pairs having similar pivot pins 11 held by thin plate discs 12, and all secured by keys 13or otherwisefrom lateral movement on the shaft. On these pins 11 are mounted a like number of (four) hammers 14, having heads bent backward and inward toward the middle hammers so as to throw the entering feed from both end sections into the path of the pulverizing hammers in the middle section. Three sets of hammers are thus providedin this construc- As these twisted, feed-deflecting hammers are pivoted opposite the spaces between the pulverizing hammers (Fig. 2), the partly ground material is thrown between-instead of against-the shanks of the pulverizing hammers, and this arrangement promotes eifi-- cient action, as well as practically avoids wear on the end faces of said shanks.

There is nothing between the ends of the feeding hammers and the circumferential spaces of the central pulverizing hammers, so that the feed material is directed inward from both ends of the casing from the oppositely I twisted ends of the feeding hammers and practically avoids wear on the shanks of the stirrup hammers.

As it is preferred to leave quite a space between the end casing and the feed. hammers forthe entrance of feed material, the feed that is not intercepted by the feed hammers on enterlng, drops down past the shaft to the bottom of the outer sections. 1' have therefore I provided a plate 15, secured to the inside face of each end casing (Fig. 1), and bent inward below the shaft, adapted to deflect the feed into the path of the feed hammers. By this arrangement, the feed is thrown into the middle section from all around the ends of the rotor and periphery of the sections, and into the spaces between the pulverizing hammers in the preferred alternate arrangement above described. V

The feed is delivered to the outer sections in regulated quantities through said preferred top openings, by right and left. hand screw blades on a shaft 16 extending in opposite directions from a feed hopper 17 mounted above a tubular casing 18 having discharge outlets 19 extending downward near the front of the respective openings 9. The feed screw is rotated through a ratchet or other wheel 20 thereon. At the rear of this feed screw casing, the balance of each opening 9 is connected by a leg 21 to a suitable separator 22 subject to the suction of an exhaust fan (not shown), in the usual or any approved manner.

Air inlets 23 are provided at the end casings or elsewhere, and are preferably screened to prevent the larger particles of feed being thrown out. A circular segment 24 with matching holts-or other regulating means allows of regulating the size of the air inlets and quantities of air admitted. The pulverized material isthus drawn outward through the openings 9 which also serve to admit feed material as above described.

Tests of this mill have indicated high efiicienc as a pulverizer. Thus, with a rotor 32" diameter operating on petroleum coke at 1180 R. P. M., the following percentages'of fineness were obtained:

79% through 325 mesh.

89% through 200mesh.

97% throu h 100 mesh.

All through mesh.

I claim': 7

1. A mill pulverizer comprising a horizontal cylindrical casing having an opening for feed anddischarge near one end, and a rotor shaft having sets of pivoted hammers operatively mounted in said casing, the inner set beingpulverizing hammersand the outer set being primary crushing hammers inclined 1nward and'respectivcely disposed opposite the open circumferential spaces-between said ulverizing hammers, substantially as descri 2. A mill pulverizer comprising a horrzontal cylindrical casin'ghavin openings for feed and discharge near the en s, and a rotor shaft having three sets of pivoted hammers mounted in said casing, the middle set being pulverizing stirru hammers and the outer sets being incline inward andrespectively mounted opposite the open unobstructed circumferential spaces between the hammers of the middle set and adapted to deflect the feed from both ends of said casin into the path of the middle set, substantial y as described.

3. A mill pulverizer comprising a horizontal cylindrical casing having upper openings for feed entrance and discharge of pulverized product near each end of said casing and providing an annular centrally disposed bull ring forming a complete circle and rinding surface and open at o posite ends f%r'unobstructed entrance of eed in both directions, a rotor shaft mounted in said casing, pivoted stirrup hammers operatively mounted on said shaft and cooperating with said bull ring for pulverizing action, a set of feeder hammers carried by said shaft at each end of said casing, and means to deflect the feed material from each end easing into the path of said feeder hammers, substantially as described.

4. A mill pulverizer comprising three cylindrical sections detachably connected together,the end sections forming the ends of a casing and having upper openings adapted for feed inlet and outlet of pulverized material and the middle section forming a complete circle and having a pulverizing surface,a rotor shaftmounted in. said casing, stirrup hammers operatively mounted on said shaft and coacting with said pulverizing surface of the middle section, and a set of rotary pivoted hammers operatively mounted near each end casing and having their ends bent inward and backward adapted to deflect the feed material into the middle pulverizing section and disposed respective yopposite the circumferential spaces between said pivot hammers, substantially as described.

5. A mill pulverizer com zontal cylindrical casing having upper openings for feed inlet and discharge of pulverized material near its ends,-the centrallljyl disposed portion of said casing forming a f circle with pulverizin sur ace and unobstructed at each endor lateral feed1ng, a

rotor shaft mounted in said casing, pulverizing hammers operatively mounted on said shaft opposite said pulverizing surface, feedin hammers operatively mounted at each si e of'said pulverizing hammers, a feed shaft having right and left hand screw blades, a tubular casin therefor delivering to said feed inlets, a eed hopper centrally disposed on said feed shaft, anda separator having le connected to said discharge openings, su stantially as described.

6. A mill pulverizer comprisin ha'vin opemngs ada ted-for fee' entrance and 'scharge of pu verized product near each end,-'-th e central portion of said casing forming a complete .ed for pulver zing action ta rotary shaft mounted in said'eas ng, a een spoo spacer rislng a horia casing circle and surface adapt on said shaft and outerspacers cooperating therewith, a. pair of perforated discs between the center spacer and each outer spacer, stirrup hammers having legs with eyes respectively disposed between said pairs of discs, and having heads cooperating with said grinding surface, pivot pins passing through said eyes and discs and controlled by said spacers, a pair of outer discs mounted on said shaft between said outer spacers and the respective ends of said casing, hammers pivotally mounted between said outer discs having ends adapted to deflect the feed inward from both directions and respectively disposed opposite the circumferential spaces between said stirrup hammers to avoid lateral wear thereon, substantially as described. i I

In testimony whereof I have aflixed my signature.

JOHN P. POLSTER. 

